Understanding and Using the hostname Command in Ubuntu

 

Understanding and Using the hostname Command in Ubuntu

Welcome, Ubuntu users! Today, we're diving into a simple yet powerful command: hostname. This command allows you to view and change your computer's hostname, which is essentially its name on a network. Let's break it down.

What is a Hostname?

Think of your hostname as your computer's "nickname." It helps identify your machine on a network, making it easier to communicate with other devices. By default, Ubuntu assigns a hostname during installation, but you can easily change it.

Viewing Your Hostname

To see your current hostname, simply open your terminal and type:

Bash

hostname

This will display the current hostname.

Changing Your Hostname (Temporarily)

To change your hostname temporarily (meaning it will revert after a reboot), use:

Bash

sudo hostname new-hostname

Replace new-hostname with your desired name. For example:

Bash

sudo hostname my-ubuntu-machine

Making Changes Permanent

To make your hostname change permanent, you'll need to edit the /etc/hostname file.

1. Open the file:

   Bash

   sudo nano /etc/hostname
   

2. Replace the existing hostname with your desired new hostname.

3. Save the file (Ctrl+X, Y, Enter).

4. Update /etc/hosts:

   Bash

   sudo nano /etc/hosts
   

   Find the line that looks like:

   127.0.0.1 your-old-hostname
   

   Change your-old-hostname to your new-hostname. It should look like this:

   127.0.0.1 your-new-hostname
   

   Also verify that the line containing your public IP address also has your new hostname listed.

5. Save the file (Ctrl+X, Y, Enter).

6. Reboot your system to apply the changes:

   Bash

   sudo reboot
   

Useful hostname Options

The hostname command also provides some useful options:

• -i or --ip-address: Displays the IP address(es) associated with the hostname.

  Bash

  hostname -i
  

• -I or --all-ip-addresses: Displays all IP addresses of all network interfaces. This is useful when you have multiple network connections.

  Bash

  hostname -I
  

• -f or --fqdn: Displays the Fully Qualified Domain Name (FQDN).

  Bash

  hostname -f
  

• -s or --short: Displays the short hostname (the part before the first dot).

  Bash

  hostname -s
  

Summary Table

Example	Description
hostname	Displays the current hostname.
hostname -i	Displays the IP address(es) associated with the hostname.
hostname -I	Displays all IP addresses of all network interfaces.
hostname -f	Displays the Fully Qualified Domain Name (FQDN).
hostname -s	Displays the short hostname.

In Conclusion

The hostname command is a simple but essential tool for managing your Ubuntu system's identity on a network. By understanding how to view and change your hostname, you can better manage your system and network connections. Happy Ubuntu-ing!

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